Offload NiFi Cluster Nodes using the NiFi Toolkit CLI (NiFi 1.8.0)

Objective

In a separate HCC article, I detailed how to offload nodes using the NiFi UI. This article covers how to perform the same operation using the NiFi Toolkit CLI.

Note: This tutorial assumes you have already setup a running NiFi cluster. The examples included are for a 2 node NiFi cluster.

Environment

This tutorial was tested using the following environment and components:

• Mac OS X 10.11.6
• Apache NiFi 1.8.0
• Apace NiFi Toolkit 1.8.0

Offload Nodes via CLI Tutorial

Queue FlowFiles

First, generate some queued flowfiles:

The queued flowfiles are distributed between both nodes in the cluster:

Disconnect Node

From a terminal window, navigate to the directory where the NiFi Toolkit was installed. From the /nifi-toolkit-1.8.0/bin directory, run:

./cli.sh


Enter the command nifi get-nodes to retrieve the node IDs:

#> nifi get-nodes
# Node ID Node Address API Port Node Status
- ------------------------------------ ------------ -------- -----------
0 dfa62636-479b-4456-aa16-3bfc19f35cb5 localhost 9443 CONNECTED
1 20a68479-e8dc-46c9-8612-872200e2fdab localhost 9444 CONNECTED


Note: If you see the error "ERROR: Error executing command 'get-nodes' : Error retrieving node status: Unable to view the controller. Contact the system administrator." You need to add "CN=localhost, OU=NIFI" to the "access the controller" view policy.

Use the command nifi disconnect-node to disconnect the node on Port 9444:

#> nifi disconnect-node -nnid 20a68479-e8dc-46c9-8612-872200e2fdab
Node ID: 20a68479-e8dc-46c9-8612-872200e2fdab
Node Address: localhost
API Port: 9444
Node Status:DISCONNECTED~


The node is disconnected:

Note: If you see the error "ERROR: Error executing command 'disconnect-node' : Error disconnecting node: Unable to modify the controller. Contact the system administrator." You need to add "CN=localhost, OU=NIFI" to both the "access the controller" modify policy.

Offload Node

Use the command nifi offload-node to offload the flowfiles on port 9444:

#> nifi offload-node -nnid 20a68479-e8dc-46c9-8612-872200e2fdab
Node ID: 20a68479-e8dc-46c9-8612-872200e2fdab
Node Address: localhost
API Port: 9444
Node Status:OFFLOADING~


Repeating the command returns the current status of the node:

#> nifi offload-node -nnid 20a68479-e8dc-46c9-8612-872200e2fdab
Node ID: 20a68479-e8dc-46c9-8612-872200e2fdab
Node Address: localhost
API Port: 9444
Node Status:OFFLOADED~


In the UI, it is confirmed that all the flowfiles have been offloaded to the active node:

Delete & Decommission Node

An offloaded node can be either connected back to the cluster ( nifi connect-node) or deleted. If the goal is to to decommission the node, use the nifi delete-node command:

#> nifi delete-node -nnid 20a68479-e8dc-46c9-8612-872200e2fdab
OK


Then after the node is deleted, stop/remove the NiFi service on the host.